Today is the Third Sunday of Advent, also called "Gaudete Sunday" (from the Latin word for "rejoice"). On this day, the pink candle, which represents joy, is lit. Traditionally, Advent was a time of fasting and penitence in preparation for Christmas, and the paraments and vestments were violet for the first two weeks. But on Gaudete Sunday, rose-colored vestments were worn and the mood was less somber and was one of rejoicing because Christmas was near.

And here's the lectionary reading for today...
http://www.usccb.org/bible/readings/121717.cfm